To understand brain function in health and disease it is essential to rapidly monitor signaling in neural circuits. Two-photon microscopy is a core tool for neuroscience research because it enables neuronal activity to be monitored at high spatial resolution deep within brain tissue. However, the mechanical scanning and focusing of conventional designs severely limits the temporal resolution of 30 imaging and brain movement complicates recordings. We have developed a novel compact acousto-optic lens (AOL) 3D two-photon microscope that overcomes these limitations, allowing high speed imaging over volumes spanning hundreds of micrometres and real time correction of the brain movement that occurs in awake behaving animals. The agile 3D random access pointing and scanning (RAPS) at 20-40 kHz bridges the gap in the temporal resolution between optical imaging and electrophysiology. Moreover, compact design features of our AOL enable it to be added to existing two-photon microscopes at relatively low cost. This proposal aims to refine and rapidly disseminate this powerful new technology. Technology refinements include expanding the volumes that can be imaged and extending AOL-based real-time movement correction from 20 to 30. The close collaboration with experimentalists in our lab and other key leading groups distributed worldwide (to whom the technology will be initially disseminated) will ensure that current and new features of the AOL, as well as the open source GUI software, are robust and meet the requirements of the neuroscience community. This will deliver new, urgently needed technological developments required for investigating neural circuits and accelerate dissemination of this world leading technology well ahead of the 3 year timescale that is required by commercial manufacturers to bring a product to market.